1. Field of the Invention
The present invention generally relates to the construction of lawnmower blades and, more particularly, is concerned with a lawnmower blade having pivotally yieldable opposite outer cutting sections for limiting or avoiding damage.
2. Description of the Prior Art
Residential lawnmowers in widespread use at the present time are of the type having an internal combustion engine mounted upon a deck and a vertical rotary crankshaft extending downwardly from the engine to below the deck. The lawnmower also has a rigid blade secured at a central region of the blade to a lower end of the crankshaft. Cutting edges are defined on opposite outer end portions of the blade which lead in the direction of rotation of the crankshaft and blade for cutting grass in a circular path as the lawnmower travels across a lawn.
Vertical crankshafts of lawnmowers of this type with the rigid blades attached directly to the lower end of the crankshafts are susceptible to bending when the blade strikes a large or solid object, such as a large rock, a tree root, etc., as the lawnmower travels across the lawn. The bent crankshaft must be taken to a mechanic for straightening before the lawnmower can be used again. Until recently, most crankshafts could be straightened one time. Now, because of the potential for liability claims to arise from injuries alleged to have been the result of inadequately straightened crankshafts, many mechanics refuse to perform this service. The lawnmower owner is then left with the choice of replacement of an expensive crankshaft or the purchase of a new lawnmower.
Consequently, a need exists for a way to prevent or minimize damage to the crankshaft in the first place.